A communication apparatus, such as a mobile phone, can be used in a plurality of frequency bands. Therefore, it is required that a module mounted in the communication apparatus deals with the plurality of frequency bands (see e.g. Japanese Patent Application Publication No. 2013-46078).
By connecting a plurality of duplexers into the communication apparatus, the plurality of frequency bands can be used. However, an electronic circuit including the plurality of duplexers is enlarged.